Sonata form in the late Baroque era (ca 1710 – ca 1750)

Properly speaking, the sonata form does not exist in the Baroque period; however, the forms which led to the standard definition are present, and, in fact, there are a greater variety of harmonic patterns in the Baroque works labelled "Sonata" than in the Classical period that is to follow. The richly diverse sonatas of Scarlatti provide examples of the range of possible relationships of theme and harmony possible in the 1730s and 1740s. Some musicologists label Scarlatti as a classical composer, and argue that the classical period begins earlier, but this is not the prevalent usage.

Sonatas were at first written mainly for the violin, and in the course of time a certain formal type was evolved, predominating until the late 18th century. This type is shown in its highest perfection in the sonatas of Bach, Handel, and Tartini – who followed older Italian models and employed a type attributable to masters such as Corelli and Vivaldi (Musical Form, Leichtentritt.

By the 1730s and 1740s the direction of instrumental works, often considered less important than vocal music, tended towards an overall two-part layout: the binary form. But a section of contrasting material which served as a bridge between them also came to be included. The symphonies of Karl Stamitz have a soft, piano interlude between forte sections.